$1 billion here, a million iPads there

The analysts who track Apple (AAPL) typically revise their estimates — usually upward — shortly before the company reports its quarterly earnings. But rumors that Verizon (VZ) might be stockpiling iPhones, and reports that Apple products are selling more briskly than expected this holiday season, have forced many to show their hands a few weeks early.

This week, several firms hoisted their Apple price targets — including Piper Jaffray (to $438), J.P Morgan ($420) and Kaufman Bros. ($395) — or lifted their line-item estimates by significant amounts. Among the most striking revisions: